I'm really curious about the range availability for that thing... It seems to be very fragile, and you have no way of getting you rocket back if you decide to abort.

I would presume whatever rig they use to drop the rocket with is recovered via parachute, so perhaps it's possible to recover the rocket that way if it doesn't launch.

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"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk"There are lies, damned lies, and launch schedules." - Larry J

This design allows them to feed 2nd and 3rd stage engines from 1st stage tank. After 1st separation, 3rd feeds from 2nd stage tank. All engines are a used, so reduced engine count on 1st stage plus more efficient as 1st stage is not lifting mass of 2nd/3rd engines.

Pressure fed, lower development cost, more reliable than turbo. Lower efficiency is counted by using all engines and them being vacuum versions.

Sea launch means no expensive launch facility with restricted flight paths. Operate off small ship, which can sail with wind so balloon is launching in still air.

Considerably lower launch forces on payload.

Not stated but the payload fairing can be light construction due to thin atmosphere.

The only area I wonder about is boil off of LOX and methane on the balloon flight.

Also working on balloon launched capsule for tourists. Issue I have with this is they are small not well funded company, need to pick one project and see it through to revenue earning stage. This is one area RL shine, laser focused on one thing.

Pressure fed, lower development cost, more reliable than turbo. Lower efficiency is counted by using all engines and them being vacuum versions.

He made a good point, which is that if you are at near vacuum ambient pressure, you can get a large expansion ratio from low Pc, you just need a large bell nozzle. If I remember correctly he said their tank pressure was going to be 10 bar (~150 psi). That's also enough that you can do some testing at sea level with a small nozzle. It's also low enough that CF tanks are going to be pretty light. Issue might be, how big can you make the nozzles before they get too heavy?

Sea launch means no expensive launch facility with restricted flight paths. Operate off small ship, which can sail with wind so balloon is launching in still air.

I'm not sure which planet he is on with this bit. Ignoring the non-trivial effects of salt water on the vehicle for the short-ish time it's exposed, to operate away from "restricted flight paths" they'd need to travel quite a distance from land - probably into international waters.

Not only is it rare to find "still air" aloft away from the protection of terra firma (ask any airline pilot), but forecasting calm patches of ocean is tricky also. They do exist in the "horse latitudes" at certain times of the year, but not for long and probably not often enough for any kind of useful or reliable launch schedule. ..and since the calm occurs before the storm, I do hope their "small ship" is robust enough to handle a spot of nasty weather lest their entire operation be sunk.

« Last Edit: 04/11/2017 04:49 AM by CameronD »

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With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they aregoing to land, and it could be dangerous sitting under them as they fly overhead.